The present invention relates to a device for continuously feeding tablets, capsules or caplets one by one into a packaging device.
There are several devices that have been used to individually dispense tablets, capsules or caplets from a bulk storage container. One common approach is to provide a turnstile that rotates to transport the tablets, capsules or caplets from a reservoir to an exit port. This type of mechanism has been used in hand-held medicine dispensers as well as in medicine packaging machines. U.S. Pat. No. 4,782,980 to Heimlich et al. and U.S. Pat. No. 5,791,515 to Kahn et al. disclose hand-held medicine dispensers that use turnstile mechanisms. U.S. Pat. No. 4,903,861 to Yuyama discloses another medicine feeder that uses a turnstile mechanism. Sadek et al. in U.S. Pat. No. 5,459,983 disclose a tablet enrobing apparatus in which a turnstile mechanism is used to feed individual tablets into a packaging strip.
Several problems have been encountered in using turnstile mechanisms to dispense tablets. Two important problems are jamming and dispensing more than one tablet from a single cavity. To some extent these problems can be solved by sizing the cavities of the turnstile to be only slightly larger than the tablet being dispensed. Yet, choosing that solution means that each turnstile can only be used for tablets of a single size or perhaps tablets within a very narrow size range.
About 80% of the medicines used in today""s hospitals are in solid form, namely, tablets, capsules or caplets. Some drugs are available in different dosage amounts. Ibuprofen, for example, is available in 200 mg. tablets and 500 mg. tablets. Health care providers often call each unit dose a xe2x80x9cmedxe2x80x9d while many patients call them pills. Thus, a hospital pharmacy would stock two different xe2x80x9cmedsxe2x80x9d of ibuprofen. Additionally, each med could be available from multiple manufacturers. For example, forty drug companies manufacture ibuprofen. These manufacturers may make the same med (e.g. 200 mg. Ibuprofen tablet) in different sizes and forms. Each med made by a manufacturer has a unique drug code, called the National Drug Code or NDC in the United States and the Drug Identification Number or DIN in Canada. Currently, there are over 12,000 unique drug codes for tablets, capsule and caplet forms of medicine. The tablets can have a diameter of from 0.150 inches to 0.710 inches (3.81 mm to 18.03 mm) and a thickness of from 0.064 inches to 0.590 inches (1.63 mm to 14.99 mm). Baker APS currently offers a medicine feeder that has interchangeable dials that operate as turnstiles. The Baker APS device requires 1,000 dials to be able to dispense 10,000 unique drug codes. A user must determine the dimensions of the NDC unit (e.g. diameter and thickness of the tablet) to be dispensed and then select the dial assigned to that size of unit. Although the device works well, the need to purchase and store large numbers of dials is costly. Thus, there is a need for a reliable medicine feeder that can dispense a large number of different meds from multiple manufacturers without requiring thousands of different turnstiles.
Although there are over 12,000 different drug codes that cover the 880 medications currently available in tablet, capsule and caplet form, most hospitals carry only a few thousand NDC units. However, we have learned that about a fourth of these medications are not used regularly and only about 30 medicines account for 30% of the demand for tablets, capsules and caplets. But, since each of the popular meds may be made by several manufacturers, there are about 800 NDC numbers that correspond to these most popular meds. The top 100 tablets, capsules and caplets are represented by about 1100 NDC codes and the top 300 such products have about 2,000 NDC codes. Consequently, a medicine feeder that can dispense individual units of about 2,000 NDC units, or even the most popular meds from multiple manufacturers rapidly, and without jamming while requiring only 200 or fewer interchangeable turnstiles rather than 2,000 such mechanisms would represent a significant advance in the art.
The current medicine dispensing machines that can feed and package more than one med have multiple feeders, each containing a different med. But, there is a common passage through which all meds pass when traveling from the feeders to the package. Small particles sometimes break off one med traveling through the common passageway as fragments or powder and can adhere to another med subsequently passing through the same passageway causing contamination. Thus, there is a need for a machine feeder in which meds can be delivered from their bulk container to a package without becoming contaminated.
Another problem that can occur in packaging solid forms of medicine is that tablets, capsules and caplets sometimes break into several pieces. The feeder should be able to detect when a fragment is present and divert the fragment away from the packaging line or remove packages containing a fragment. This is particularly important when the medicine is being packaged in unit dose packages.
We provide a unit dose medicine feeder that can dispense tablets, capsules and caplets individually from a reservoir. This feeder has a housing that is on a base that defines a reservoir or chamber. The base has an opening through which tablets, capsules and caplets may pass. There is a wheel-like component, called an indexer wheel, on the base that has a plurality of slots about its outer periphery. The slots are sized to receive a single tablet, capsule or caplet and are oriented so that the wall of the slot is from 10xc2x0 to 45xc2x0 away from vertical. A gear mechanism is provided to connect the indexer wheel to an electric motor such as a stepper motor having position feed back capability. This motor rotates the wheel-like component. That rotation will sequentially align the slots with the opening in the base allowing a tablet, capsule or caplet within the slot to pass from the slot through the opening. A retainer is attached to the wall of the housing, opposite the opening in the base and adjacent the top of the wheel. The retainer covers that slot which is aligned over the opening. The orientation of the slots enables the wheel to receive a wider range of tablets, capsules and caplets without jamming and without dispensing more than one unit from a slot.
We further prefer to connect the electric motor to the indexer wheel through a coupling having a ring gear that is driven by the motor and a position ring with slots on it. The position ring is adjacent the ring gear and turns with the ring rear. A sensor is provided opposite the position ring to sense the rotation of the indexer wheel. When a jam is sensed the motor reverses direction to clear the jam. The motor may run through a few steps to allow the jam to clear then resume the original rotation. Alternatively, the motor may continue in that opposite direction until another jam occurs and then reverse direction to clear the jam.
The feeder also has a gate or trap door that directs the med leaving the feeder directly into the package. Hence, there is no need for a chute to be positioned above the package. Since each feeder has a gate that allows for dropping the med directly into the package, the common chute and the associated contamination can be eliminated.
A sensor is preferably provided at the bottom of the feeder to detect the med as it passes from the indexer wheel toward the gate. The sensor tells the control system or operator when a tablet, capsule or caplet has been dispensed. Additionally, the sensor can be configured and positioned to also detect when a fragment has been dispensed. Then steps can be taken to remove the fragment or remove a package containing the fragment.
A machine vision system can be placed near or incorporated into the feeder to take an image of the medicine being dispensed. That image can then be compared to a reference image to positively identify the medicine being dispensed.
We have found this dispenser to be very reliable in not dispensing multiple units from a slot and in not presenting empty slots to the openings in the base.
Other objects and advantages of the medicine feeder will become apparent from certain present preferred embodiments thereof that are shown the drawings.